With just one airline offering flights to and from the Western Isles, Orkney and Shetland, there is a lack of competition to keep prices low.
However the infrastructure available at island airports and the size of aircraft required for the service could be deterring other budget airlines from moving in.
A spokesperson for EasyJet said this week: “I am afraid that due to aircraft size we operate and the runway size we are unable to consider operating these routes.
“The only one we could operate would be into and out of Stornoway but at this time this is not something we are considering.”
She added that they were committed to expanding the Scottish network but not in this area at the moment.
A spokesperson for Ryanair said: “We are concentrating on growing our UK domestic traffic at present, with our Edinburgh service to London extending to 5 times daily for the winter, alongside our 4-times daily Glasgow-London service.”